Social touch can convey the most potent and salient of socio-emotional signals. While the hypothalamic peptide oxytocin (OXT) has been identified as a key neurochemical mediator of grooming in some other social species, its modulatory influence on human interpersonal touch is unknown. The investigators expect that OXT augments the hedonic value of touch and that this behavioral effect is paralleled at the neural level by an increased response in brain areas mediating rewarding aspects of social touch.